Preparation and utilization of carbon-based adsorbent from organic pollutants in waste salt during acidic blue AS dye production
The salt-containing wastewater discharged from the production of the dye weak acid blue AS(AS)is spray-dried to make waste salt,and then the organic pollutants are calcined to prepare a quasi-activated carbon adsorbent(LAC).It was utilized for the adsorption and decolorization of wash wastewater from AS dye production.Additionally,the crude salt(NaCl)recovery from the above calcination technology could be reused in the salting-out process in AS industrial production.This research was conducted to determine the optimal temperature for calcining LAC,and calcination in a muffle furnace at 450℃yielded the best results.Furthermore,the impact of initial dye wastewater concentration,temperature,and pH on the adsorption performance of LAC was investigated.The findings revealed that,in AS dye wastewater with an initial concentration of 40 mg/L,the adsorption at 318 K was more effective than at 298 K and 278 K.At 318 K,the equilibrium adsorption capacity was 29.22 mg/g,and acidic conditions favored the adsorption process.The adsorption kinetics study on LAC indicated that the pseudo-second-order kinetic model better fitted the adsorption results.Thermodynamic analysis revealed that the Langmuir isotherm equation provided a better fit for the adsorption experimental results.Moreover,investigations into the cyclic regeneration performance of LAC demonstrated its good regenerative capabilities,and could be reused several times.Even after four cycles,the adsorption rate for AS dye remained above 80%.Additionally,a modification using a one-pot mixed approach with addition of magnesium acetate tetrahydrate improved the surface area of adsorbent LACMg0.75 by nearly 5 times compared to LAC,achieving a saturation adsorption capacity of 550.02 mg/g,nearly 20 times higher than that of LAC.
acidic blue ASwastewater treatmentadsorbentrecycleactivated carbontreating waste with waste
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